cyamamot@nunki.usc.edu (Cliff Yamamoto) (04/04/89)
Greetings, Does anyone out there own a car with one of the new Bose stereo systems? I recall Corvette and Lincoln were just a couple of cars that came with them. My problem is I'd like to add a CD player and subwoofer to one of these systems. Specifically, the car is a 89 Nissan Maxima with a Bose stereo. All four speakers are individually amplified. However, upon checking the signal level applied to the amps, it appears the inputs are differential. Both signal lines are ~5 volts above chassis ground and .4-.6 volts measured between the two. Yet, when I tried connecting the inputs to an amplifier with line level inputs the sound was barely audible. Then when I tried connecting a regular 1 volt line level output to the input of the speaker amplifier, I hear the speaker squeal. These signal lines between the head unit and each amp are unshielded (or appear to be)! Because of that I'm just guessing that it is differential. Does anyone know if someone makes a preamp or some sort of interface that can convert differential signals to standard line level signals. Is what I'm experiencing characteristic of those 3-pin balanced line XLR connections? Isn't balanced line equivalent to differential input? If all else fails I'll just have to find a tap inside the head unit or inside 2 of the amplifiers that's close to line level. The head unit and the speakers are fine, which is why I'd like to retain them. It just needs a CD player and a little reenforcement on the lower frequencies. Thanks for any advice Cliff Yamamoto